If a panicked diver comes from behind you, you won't be able to stiff arm them if they grab your primary. While grabbing a bungeed octo under your chin is faster than an Air2, I don't think it is significantly faster. As a photographer, I probably won't see an OOA diver coming.
The difference in speed between getting the two versions of the alternates to your mouth is not an issue worth arguing about. If you keep your head, you can take your sweet time getting your alternate--a difference of a second or two won't make as much difference to you as it will to the OOA diver. That diver will usually want the air fast because of the state of mind; you should be more in control.
So how will that OOA diver act?
In my 11+ years on ScubaBoard, I have read countless threads in which people tell us with firm conviction how an OOA diver is going to act. I think I have seen every possibility asserted with that firm conviction. The only time I have been even near a real OOA incident was about 11 years ago, when I first became a professional. In that incident, a young woman had evidently geared up to a nearly empty tank and had not noticed the air level, because she went OOA about 10 minutes into the dive. She calmly swam over to her husband and took his octo. They completed a textbook ascent after that, with the rest of their group calmly ascending with them. Curious, I polled the other professionals associated with the shop and learned that only a handful had been near OOA emergencies, and every case was like that--the OOA diver went for the alternate without any sign of panic.
So do I assume that all OOA emergencies will be like that? Nope. I assume that those who report other situations are telling the truth, so I really cannot predict what will happen in a real OOA emergency. That is why I tell my students they have to be ready for anything. In my own practice, I have made the following decisions.
1. I need to react appropriately to that diver. Signalling OOA? Here's your regulator. Grabbing for my regulator? Take it--I'll let you. If I try to donate it while you're taking it, we can end up with a fumbled mess as our hands compete with each other's.
2. The last thing I want to do is get in an underwater fight with a truly hysterically panicked diver. If I think that person is going to crawl all over me and harm me, I will fend that person off, but otherwise the OOA diver is usually going to get what he or she wants. Unexpectedly ripping the regulator out of my mouth? Be my guest. I'll open wide so I don't lose any teeth. We can sort things out later.
3. I learned the bungeed alternate in tech diving and then brought it into my recreational practices when I heard about a woman who drowned when she went OOA. Her buddy's octo had come out of its holder and she could not locate it. An OOA diver will want guaranteed access to a working regulator immediately, and the one in my mouth will do nicely. I'm happy to loan it out.
4. I learned about the long hose primary in tech diving and brought it into my recreational practices as well. It gives me lots of options in dealing with that diver. Donating the long hose is fast and easy, much faster and easier than donating the octo from the golden triangle. We can cling to each other as in the standard octo process, or we can separate and swim either next to each other or in single file, whichever makes the most sense in the situation.
5. I am not opposed to the integrated octo on the inflator hose to the degree most tech divers are. It can work. What I mostly don't like about it is the complications of venting air from a hose with the end in your mouth as you ascend while your right arm is engaged with the other diver (assuming a short hose). I've never done it, but I do know it requires you to do something you probably have never really practiced at a time when your mind might be otherwise occupied.
